[回声字幕修复]：完成播报阶段实时字幕隔离，包含静默打断判定和回归测试

tests/test_live_runtime.py

@@ -541,10 +541,12 @@ class LiveRuntimeTests(unittest.TestCase):
         summary = runtime.run(max_turns=2)
         event_types = [event.type for event in runtime.event_bus.events]
         context_texts = [message.content for message in runtime.context.messages()]
+        playback_window = event_types[event_types.index(TTS_STARTED) : event_types.index(PLAYBACK_INTERRUPTED)]
 
         self.assertEqual(summary.completed_turns, 2)
         self.assertIn(BARGE_IN_DETECTED, event_types)
         self.assertIn(PLAYBACK_INTERRUPTED, event_types)
+        self.assertNotIn(TRANSCRIPT_PARTIAL, playback_window)
         self.assertIn("已播出一句。", context_texts)
         self.assertNotIn("这是一段需要被打断的很长很长很长很长很长很长很长很长的回复内容，没有播放完。", context_texts)
         self.assertEqual(reporter.transcripts[-1], "打断问题")